Conflicts of interest: None.
Investment choices in post-embryonic development: Quantifying interactions among growth, regeneration, and asexual reproduction in the annelid Pristina leidyi
Article first published online: 2 AUG 2013
© 2013 Wiley Periodicals, Inc.
Journal of Experimental Zoology Part B: Molecular and Developmental Evolution
Volume 320, Issue 8, pages 471–488, December 2013
How to Cite
2013. Investment choices in post-embryonic development: Quantifying interactions among growth, regeneration, and asexual reproduction in the annelid Pristina leidyi. J. Exp. Zool. (Mol. Dev. Evol.) 320B:471–488., .
- Issue published online: 5 NOV 2013
- Article first published online: 2 AUG 2013
- Manuscript Accepted: 20 JUN 2013
- Manuscript Revised: 16 APR 2013
- Manuscript Received: 9 JAN 2013
- National Science Foundation. Grant Numbers: IOB-0520389, IOS-0920502
- University of Maryland Graduate School
- Behavior, Ecology, Evolution, and Systematics Graduate Program
Animals capable of multiple forms of post-embryonic development, such as growth, regeneration, and asexual reproduction, must make choices about which processes to invest in. What strategies guide post-embryonic resource allocation investments? We investigated this question in the annelid Pristina leidyi, which can grow continuously, regenerates well, and reproduces asexually by fission. We found that in this species growth is concentrated in three zones: a subterminal posterior zone (forming new segments), a mid-body zone (forming fission zones), and a previously undescribed subterminal anterior zone at the base of the prostomium (which we suggest continually builds the prostomium through a “conveyor-belt” like process). Body-wide counts of proliferating cells are greater under high food than low food conditions but proliferation patterns themselves are independent of feeding level. Proliferation patterns are strongly affected by amputation, however, with proliferation rapidly shutting-down throughout the body, except at the wound site, following injury. Relative investment to fission and regeneration is highly context-dependent, being sensitive to the position of the cut and the stage of fission. Outcomes range from fission acceleration and regeneration stalling (high fission:regeneration investment) to resorption of fission zones and progression of regeneration (low fission:regeneration investment). Our findings reveal strong interactions between growth, regeneration, and fission and demonstrate a particularly important effect of injury on resource allocation patterns. Patterns of resource investment in P. leidyi show similarities to those described in two other groups that evolved fission independently (naidine annelids and catenulid flatworms), suggesting that similar developmental and physiological contexts may drive convergent evolution of resource allocation strategies. J. Exp. Zool. (Mol. Dev. Evol.) 320B: 471–488, 2013. © 2013 Wiley Periodicals, Inc.